1. Field of the Invention
This invention relates to an electro-luminescence display device, and more particularly, to an organic electro-luminescence display device and a method of fabricating the same that is capable of reducing an inverse taper of a bus electrode.
2. Description of the Related Art
Recently, there have been developed various flat panel display devices reduced in weight and bulk that is capable of eliminating disadvantages of a cathode ray tube (CRT). Such flat panel display devices include a liquid crystal display (LCD), a field emission display (FED) device, a plasma display panel (PDP) and an electro-luminescence (EL) display device, etc. device. Especially, the EL display device has characteristics of a wide viewing angle, a high aperture rate and a high color purity, etc., such that it can be highlighted into a post-generation display device.
Such the EL display device comprises an anode electrode and a cathode electrode 12 with an organic layer therebetween, wherein the organic layer includes a hole carrier layer, a light-emitting layer, and an electron carrier layer. Electrons and holes emitted from these anode electrode and cathode electrode are re-combined with each other, thereby generating a visible light. At this time, the generated visible light is emitted, via the anode electrode, into an exterior to thereby display a predetermined picture or image.
Meanwhile, as shown in FIG. 1, an anode electrode 52 includes: a transparent 56 formed on a substrate 51; and a bus electrode 54 formed on one side of the transparent electrode 56 to compensate a resistance component of the transparent electrode 56.
Herein, the bus electrode 54 is formed by etching a chrome Cr, a molybdenum Mo, and a copper Cu, etc. using an etchant consisted of phosphoric acid in a rage of 60 to 65 weight %, nitric acid in a range of 5 to 6 weight %, acetic acid of 10 weight %, and water in a range of 19 to 25 weight %. An inclination angle of the bus electrode 54 formed by using the etchant is relatively large as about 80° to 110°. Accordingly, a taper of the bus electrode 54 is deteriorated. In other words, the bus electrode 54 is formed in an inverse taper type in which the lower portion thereof has a narrower width than the upper portion thereof. An insulating film 58 formed to cover the anode electrode 52 having the bus electrode 54 makes a step coverage to be deteriorated, so that a pinhole A exposing the bus electrode 54 is occurred as shown in FIG. 2. An insulation breakdown is occurred by the pinhole, so that there is a problem that a reliance of the electro-luminescence display device is deteriorated, e.g., the anode electrode 52 and a cathode electrode are shorted.